Polymeric pyridinium ylides and products prepared from same

ABSTRACT

Polymers containing pyridinium ylide moieties are subjected to actinic irradiation to convert the pyridinium ylide moieties to water-insoluble or hydrophobic N-acyl-diazepine polymers. The polymeric pyridinium ylides can be used for the waterproofing or hydrophobization of surfaces and for the production of printing plates, photoresists, printed circuit boards and the like.

BACKGROUND OF THE INVENTION

This invention relates to certain polymeric produces prepared frompyridinium ylides. More particularly, it relates to hydrophophic,protective polymers and to articles, including photoresists, preparedfrom polymeric pyridinium ylides by a photolytic reaction.

The use of photopolymerization reactions in the printing and graphicarts fields for the production of relief and lithographic printingplates has been well known. Suitable methods for the production ofplates for the printing and graphic industries are described, forexample, in Neblette's Handbook of Photography And Repography, SeventhEdition, pp. 439-40 (1977). Typically, a monomeric compound on asuitable plate support material will be selectively exposed to a sourceof light so as to effect a photopolymerization (insolubilization) inexposed areas. The difference in solubility, between unexposed andexposed (polymerized) areas, permits easy development.

The principles of photopolymerization are also utilized inphotoengraving and lithographic plate-making by the use of long-chainpolymers whose molecules are able to crosslink under the action of lightto form a three-dimensional molecular network. Typically, thephoto-crosslinked polymer will be insoluble, and will be soluble only inpowerful solvent mixtures of the type used in paint stripping. Stencilsproduced by the photo-crosslinking reaction are photoresists which arehighly resistant to commonly used solutions; solvent development is usedto remove the original long-chain polymer from unexposed areas.

In U.S. Pat. No. 3,081,168 (issued Mar. 12, 1963 to R. M. Leekly etal.), the production of relief plates using polyamides as a preformedpolymer is described. Photosensitivity is imparted to the polyamide,which is carried on a support, by including with the polyamide, aphotopolymerizable unsaturated compound. Following a selective exposureto light, which induces a decrease in solubility in exposed areas,unexposed areas are removed with a developer. After development, thebase material (e.g., metal) can be etched by chemical etching orabrasive blast to form a relief image in the base material. If desired,an offset plate can be prepared by coating the photosensitive polyamidecomposition onto a hydrophilic support. The image obtained uponphotoexposure and development will carry an ink and the wet support willresist ink.

In the production of plates by resort to photoreaction chemistry, areactive and photopolymerizable monomeric compound will oftentimes beemployed. The compounds are frequently liquid or in a gaseous form whichmay hamper efficient handling and the production of coatings suited tophotopolymerization. Preformed polymers which are photo-crosslinkablemay exhibit limited photo-reactivity or sensitivity. Accordingly, itwill be appreciated that there will be application in photosensitiveplate-making for a polymeric compound which can be conveniently coatedfrom an aqueous medium onto a suitable substrate or carrier material andwhich can be readily converted, by a chemical modification induced byexposure to irradiation, to an insoluble or hydrophobic material.

SUMMARY OF THE INVENTION

It has been found according to the present invention that products andarticles including a hydrophobic or water-insoluble protective polymermaterial can be prepared by subjecting a layer or coating of a polymericpyridinium ylide to a source of actinic irradiation sufficient to inducea chemical modification thereof and production of the hydrophobic orwater-insoluble protective polymer material. According to one of itsproduct aspects, the present invention provides a photosensitive articlecomprising a suitable substrate material carrying a layer ofphotosensitive pyridinium ylide polymer, the polymer being adapted, uponexposure to actinic radiation, to conversion to a water-insoluble orhydrophobic protective polymeric material.

According to one of its method aspects, there is provided a methodwhereby an article carrying a layer of photosensitive polymericpyridinium ylide is irradiated sufficiently to induce a photochemicalmodification of the polymer and resulting water insolubility orhydrophobicity. A preferred method comprises selectively irradiating anarticle carrying a layer of photosensitive polymeric pyridinium ylide,to convert exposed areas to a water-insoluble or hydrophobic material;and washing from the article, in areas of non-exposure, the unexposedpolymeric pyridinium ylide; thereby to provide an image inwater-insoluble or hydrophobic polymeric material. Certain novelpolymers, compositions containing photosensitive polymeric pyridiniumylides, and methods for the use thereof are provided by the presentinvention. Objects of the present invention, details, constructions,operations, uses, advantages and modications thereof will be apparentfrom the following description, taken in conjunction with theillustrative drawings of certain embodiments thereof.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a cross-sectional edge view of a photosensitive article of theinvention.

FIG. 2 is a cross-sectional edge view of a photosensitive article of theinvention carrying an optional metallic layer.

FIG. 3 is a plan view of an enlarged scale of a metallic electrodepattern formed on a substrate material.

FIG. 4a is a cross-sectional view of an electrode pattern taken alongthe lines 4a--4a of FIG. 3 and showing a support carrying electrodeshaving a protective polymeric layer thereon.

FIG. 4b is a cross-sectional view of the electrodes of FIG. 4a with theprotective polymer removed therefrom.

FIG. 5 is a plan view of an image in hydrophobic polymer material formedon a substrate material by the method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the production of products of the invention, a layer or coating ofpolymeric pyridinium ylide is converted by actinic radiation to apolymeric material exhibiting water insolubility or hydrophobicity. Thepyridinium ylide polymers suited to this purpose are polymers whichinclude the pyridinium ylide moieties of formulas (I) and/or (II):##STR1##

wherein X is ##STR2## and R¹ is alkyl, aryl, alkaryl or aralkyl. Thesemoieties, are a part of the polymer and are either pendant from thepolymeric backbone, as in the case of the moiety of formula (I) or (II),or comprise a part of the backbone of the polymer, in the case of themoiety of formula

(II). Preferred X groups include ##STR3## and --SO₂ --. Polymers whichcontain these pyridinium ylide moieties are for convenience referred tohereinafter as polymeric pyridinium ylides.

When a polymeric pyridinium ylide containing the moiety (I) or (II) issubjected to photolysis, the resulting chemical modification (aconversion of the pyridinium ylide to an N-acyl-diazepine viaring-expansion) is accompanied by a substantial change in polymerproperties. While the pyridinium ylide polymer is generallywater-soluble and can be conveniently coated from an aqueous coatingmedium onto a suitable substrate material, the correspondingN-acyl-diazepine polymer produced upon irradiation is characterized byinsolubility in water, or hydrophobicity. This substantial change inpolymer properties makes possible the application of pyridinium ylidepolymers to the production of various articles, including photoresists,stencil coatings, duplicating pads, lithographic and relief plates,printed circuit boards and chemically etched electrode patterns on glassor other supports.

The chemical conversion (N-acyl-diazepine formation) can be illustratedby resort to the following scheme showing the conversion of a polymerhaving a preferred pyridium aminimide moiety to the correspondingN-acyl-diazepine: ##STR4##

The accompanying changes in physical properties permit a variety ofproducts to be prepared as mentioned hereinbefore. Accordingly,variations in the nature of the polymer can be used to accommodateparticular applications. According to a preferred embodiment of theinvention, the polymer will comprise a backbone having pendantpyridinium ylide moieties, the polymer comprising repeating unitsaccording to the formula (III) ##STR5## wherein L represents an organiclinking or spacer group which serves to link the ##STR6## moiety to thepolymer backbone; and m is the integer one or two.

It will be seen from inspection of the polymer unit represented byformula (III), that the pyridinium ylide moiety pendant from the polymerbackbone may be attached either directly to the backbone (as where m isone) or through the organic linking group, L (m is two).

Preferably, the backbone of the polymer will comprise a plurality ofinterconnected units corresponding to the formula ##STR7## where R² ishydrogen, halogen or alkyl, such as can be readily provided by ethylenicpolymerization of acrylic or methacrylic monomers.

The nature of organic linking or spacer group L can vary and, forexample, can be a divalent radical such ##STR8## --Ar--; or --Ar--R³ --(wherein R³ in each such radical represents a divalent alkylene radical,such as methylene, ethylene or 1,2-propylene; R is hydrogen, alkyl,aryl, alkaryl or aralkyl; and Ar represents an arylene radical such asphenylene or naphthylene). In each of the L groups containing a carbonylgroup, such carbonyl group will preferably be attached to the backboneof the polymer. It will be appreciated that the nature of linking groupL, and its molecular configuration and size, can be varied to influencethe properties of the polymer produced by photo-induced modification,and the rate of the desired photo-reaction; and the choice of a suitablelinking group may in part be influenced by synthetic considerations andready availability of reactants for production of pyridinium ylidepolymers hereof.

A preferred linking group L has the formula ##STR9## wherein R³ is adivalent alkylene group such as ethylene. Preferred polymeric ylideshaving this linking group are the polymeric pyridinium aminimides##STR10## Repeating units of such preferred polymers will have theformula (IV): ##STR11## wherein R² is hydrogen, halogen (e.g., chloro)or lower alkyl (e.g., methyl); and R³ is alkylene. Polymers having therepeating units shown in formula (IV) contain a carbamate structure andcan be conveniently obtained by polymerizing the reaction product of anisocyanatoalkyl ester (such as beta-isocyanato-ethyl methacrylate) andN-amino-pyridinium compound. The resulting polymers are readilyconverted to a water-insoluble or hydrophobic polymer upon irradiationand can be used in the manufacture of photoresists and printing plates.

The linking group L of the polymers shown in formula (III) can, ifdesired, be attached to two carbon atoms of the polymeric chain. Asuitable example is the radical ##STR12## derived, for example, from apolymerizable maleimide. Such a linking group can be present in therepeating unit of a pyridinium ylide polymer such as is represented bythe unit of the formula ##STR13##

If desired, the pyridinium ylide moiety of polymers useful herein can beincorporated into the backbone of a polymer. In this case, a suitablepyridinium ylide moiety is the moiety of formula (II), i.e., the##STR14## A polymer including the pyridinium ylide moiety of formula(II) as part of the backbone is illustrated, for example, by referenceto repeating units of the following formula (V): ##STR15## wherein R⁴ isalkylene or arylene; R⁵ is alkylene, such as 1,3-propylene; and X hasthe meaning described hereinbefore. A polymer as represented by formula(V) can be prepared by reaction of a dicarboxylic acid halide of theformula ##STR16## where each Z is halo (e.g., chloro) and abis-amino-pyridinium compound of the formula ##STR17## wherein R⁴ and R⁵have the meanings aforedescribed and each A.sup.⊖ is a counteranion,such as chloride.

Another example of a pyridinium ylide polymer where the formula (II)moiety is present in the polymer backbone is illustrated by the polymerhaving aminimide repeating units of formula (VI) ##STR18## Such apolymer can be prepared by reaction of a diisocyanate of the formula R⁶--N═C═O)₂ wherein R⁶ is alkylene or arylene with a 1-amino-pyridiniumcompound of the formula ##STR19## wherein A.sup.⊖ is a counteranion(e.g., chloride).

If desired, a pyridinium ylide polymer wherein the pyridinium ring isattached to the backbone of the polymer can be employed herein. Anexample of such a polymer is a polymer comprising repeating units of theformula (VII) ##STR20## wherein R⁷ is alkyl; alkoxy; aryl (e.g.,phenyl); alkaryl (e.g., tolyl); or aralkyl (e.g., benzyl); and X has themeaning described hereinbefore. Such a polymer can be prepared, forexample, from poly(4-vinylpyridine) by: derivatization of thepoly(4-vinylpyridine) to provide the 1-amino-pyridinium (usinghydroxylamine-O-sulfonic acid and hydriodic acid treatments, accordingto the techniques described in Organic Syntheses, Collective Volume 5,John Wiley and Sons, pp. 43-45); and reaction of the resulting polymerwith an acylating agent of the formula R⁷ --X--Z wherein R⁷, X and Zhave the meanings previously ascribed. This reaction scheme isillustrated by reference to the following: ##STR21##

Examples of acylating agents that can be used in reference to theabove-described reaction scheme include: CH₃ --SO₂ --Cl; (CH₃ O)₂--P(O)Cl; CH₃ --C(O)Cl; or the esters or anhydrides thereof. Phenylisocyanate can also be used.

If desired, hydroxy-containing polymers having ylide groups attachedthereto through an ether linkage can be prepared by reaction of apolymer having a plurality of hydroxyl groups (e.g., cellulose,hydroxyethyl cellulose or hydroxypropyl cellulose) with, for example, acompound of the formula ##STR22## using the procedure described in U.S.Pat. No. 4,016,340 (issued Apr. 5, 1977 to H. S. Kolesinski et al.).

The polymeric pyridinium ylides containing the essential pyridiniumylide moieties of formulas (I) and/or (II) can, if desired, containsubstituent groups on the pyridinium nucleus. Alkyl, aryl, halo, nitroand other substituents can be used to modify the properties of thepolymeric pyridinium ylide as desired. It will be appreciated that thenature of the substituents present may alter the absorptioncharacteristics of the pyridinium ylide moiety and may influence theconditions required to effect the desired conversion to thecorresponding polymeric N-acyl-diazepine. Any substituent groups whichdo not negate or otherwise adversely interfere with the desiredconversion can, however, be employed. One or more methyl groups can, forexample, be used and examples of such substituted-pyridinium moietiesinclude 2-picolinium, 3-picolinium, 4-picolinium and3,5-dimethyl-pyridinium. Two substituent groups can taken togethercomplete a cyclic structure such as a quinolinium or isoquinoliniumstructure. As used herein, the term "pyridinium" is used to includesubstituted-pyridinium moieties, such that, moieties which may properlybe termed picolinium, quinolinium or the like, will be consideredpyridinium moieties as the term is used herein.

Among examples of polymeric pyridinium ylides that can be utilizedaccording to the invention are polymers which include repeating unitshaving the following formulas: ##STR23##

The polymers employed herein can be homopolymers or copolymers,including graft or block copolymers. The copolymers can contain unitsprovided by copolymerization with various ethylenically unsaturatedmonomers such as alkyl acrylates, alkyl methacrylates, acrylamides, andmethacrylamides. In general, these comonomeric units are utilized toprovide particular predetermined properties to the polymer, such ascoatability and viscosity and, in particular, polymerizability andcontrolled photo-reactivity.

In general, the polymers employed herein will contain the photo-reactivepyridinium ylide repeating units in an amount sufficient to allow forappreciable conversion from a relatively water-soluble condition to acondition of relative insolubility or hydrophobicity. In the copolymers,the proportion of photo-reactive units to total units will varydepending on the nature of the particular photo-reactive units employed,the nature of the comonomeric or any polymeric material that may beutilized therewith, and upon the particular application and productrequirements or characteristics desired.

A preferred comonomeric unit that can be included in a polymer of thepresent invention is the methacrylate unit obtained from thepolymerizable methacrylate monomer of the formula (XXV) ##STR24##

This monomer is readily polymerizable with the polymerizable pyridiniumylides hereof. A preferred copolymer is a copolymer of this monomer andthe preferred pyridinium aminimide monomer corresponding to therepeating unit of formula (XIII). Good results are provided uponirradiation of this preferred copolymer. Other ethylenically unsaturatedcomonomers can, however, be used and examples of such include acrylicacid; methacrylic acid; 2-acrylamido-2-methylpropane sulfonic acid;N-methyl acrylamide; methacrylamide; ethyl acrylate; butyl acrylate;methyl methacrylate; N-methyl methacrylamide; N-ethyl acrylamide;N-methylolacrylamide; N,N-dimethyl acrylamide; N,N-dimethylmethacrylamide; N-(n-propyl) acrylamide; N-isopropyl acrylamide;N-(β-hydroxy ethyl) acrylamide, N-(β-dimethylamino) acrylamide;N-(t-butyl) acrylamide; N-[β-(dimethylamnio)ethyl]methacrylamide;2-[2'(acrylamido)ethoxy]ethanol; N-3'methoxy propyl)-acrylamide;2-acrylamido-3-methyl butyramide; acrylamido acetamide; methacrylamidoacetamide; 2-[2'-methacrylamido-3'-methyl butyramido]acetamide; anddiacetone acrylamide.

Polymers hereof containing the repeating units of formulas (I) or (II)pendant from the backbone thereof can be readily prepared bypolymerization in known manner of the corresponding polymerizablemonomeric compound of the formulas (XXVI) or (XXVII) as follows##STR25## wherein X, m, L and R⁷ have the meanings hereinbeforedescribed. Various preparative routes to the polymerizable monomers canbe used depending upon the nature of the L and X moieties desired in thepolymer; and suitable synthetic methods will be known to those skilledin the art. For example, preferred polymerizable monomers useful in thepractice of the present invention have the formula ##STR26## wherein R²and R³ are as previously defined. These compounds can be prepared by thereaction of an isocyanato ester of acrylic, methacrylic or2-chloroacrylic acid having the formula ##STR27## (wherein R² and R³ areas previously defined) with a 1-amino-pyridinium salt of the formula##STR28## wherein A.sup.⊖ represents a halide counteranion such aschloride, bromide or iodide. The isocyanatoalkyl ester startingmaterials are known compounds and their method of preparation isdescribed, for example, in U.S. Pat. No. 2,718,516 (issued Sept. 20,1955 to N. M. Bortnick). Similarly, the 1-amino-pyridinium salts andtheir preparation are described in Organic Syntheses, Collective Vol. 5,pp. 43-45. The reaction is illustrated by reference to the followingreaction scheme which shows the reaction of the prepared 2-cyanatoethylmethacrylate and 1-amino-pyridinium chloride in the presence ofpotassium carbonate: ##STR29##

The ethylenically unsaturated polymerizable monomers can be polymerizedusing known polymerization techniques such as solution polymerizationusing free radical or redox initiation. Suitable initiators includeazobisisobutyronitrile and azo-bis-4-cyano-pentanoic acid, althoughother catalysts can be employed.

Condensation-type polymers in which the pyridinium ylide moiety is apart of a polymeric backbone can be prepared by resort to knownpolymerization methods used in the preparation of condensation polymers.Solution polymerization or interfacial polymerization techniques can beused depending upon the nature of the particular monomers used in thepolymerization.

The polymeric pyridinium ylides can be converted to their correspondingN-acyl-diazepines using a source of actinic irradiation of sufficientintensity. In general, ultraviolet radiation provides good results;other sources of actinic irradiation can, however, be employed. It willbe appreciated that the amount of irradiation required to effect thedesired conversion will vary with the wavelength and the intensity ofthe radiation source and will vary with the absorption properties of thepyridinium ylide moiety of the polymer employed. The absorptionproperties, can vary with the presence or absence of substituent groupson the pyridinium nucleus. Appropriate exposure times and conditions canbe employed depending upon these considerations. In general, a source ofultraviolet irradiation can be used in conjunction with exposure timesin the range from less than one to about 30 minutes or more.

The novel polymers produced from the photosensitive ylide polymers byphotolytic reaction contain N-acyl-diazepine moieties of the formulas(XXVIII) and (XXIX) ##STR30## The polymers containing these moieties arereferred to herein for convenience as N-acyl-diazepine polymers. Thesepolymers have the structure of the corresponding pyridinium ylidepolymers described herein, except for the presence of N-acyl-diazepinemoieties of formulas (XXVIII) and (XXVIX) in place of the correspondingpyridinium ylide moieties (I) and (II) of the precursor polymers.Examples of repeating units of polymeric N-acyl-diazepines of theinvention include the following, formulas (XXX) to (XXXIV): ##STR31##

It will be noted that the photolysis of aminimides derived frompyridines, and the production of diazepines therefrom, are described byW. J. McKillip et al., in Chemical Reviews, Vol. 73, No. 3, pp. 272-273(1973). The formation of pyridine and nitrene side-reaction products(and the effects of triplet photosensitizers such as eosine or3,4-benzopyrene on such formation) are also described therein. It willbe appreciated that nitrene and pyridine side-reaction products may alsobe formed in connection with the photolytic reaction employed in thepractice of the present invention. If desired, a triplet sensitizer canbe employed in combination with the polymeric pyridinium ylides of thepresent invention so as to promote nitrene or isocyanate formation andthe production therefrom of cross-linking reactions (by reaction ofnitrene or isocyanate moieties with compounds having an active hydrogenatom). Accordingly, triplet sensitization can be employed, if desired,to modify the physical properties of the polymeric N-acyl-diazepineproduced by the practice of the present invention.

The polymeric pyridinium ylides can be used for a variety of purposes,including treatment and hydrophobization of surfaces. Thus, a layer ofthe polymer can be applied from solution to a suitable substrate whichis then subjected to exposure to a source or irradiation sufficient toeffect the desired conversion of the ylide to the corresponding N-acyldiazepine. Water can be employed and will be a preferred solventmaterial for the preparation of a coating composition which can beconveniently applied to the substrate by spraying, dipping, roll coatingor the like. Other solvents can, however, be used and examples of suchsolvents are methanol, ethanol and trichloromethane. A coatingcomposition suited to application to various substrate materials willtypically contain the desired pyridinium ylide polymer in aconcentration of about 3 to 4% by weight, although other concentrationscan be used depending upon the particular polymer employed, the natureof the solvent utilized, the method of application and the nature of theparticular substrate. Various additives such as surfactants, coatingaids, viscosity-controlling agents, UV stabilizers, photoinitiators,triplet sensitizers or the like can be included, provided that suchagents do not interfere with the desired conversion of the pyridiniumylide compound to the corresponding N-acyl-diazepine.

The polymers can be used for the treatment of substrates such as glass,metal, plastic, such as polyethylene terephthalate or cellulose acetate,or fabrics. Sheets, swatches, scrims, ropes or other fibers can besprayed, dipped or otherwise coated with the polymeric ylide compoundand can be, then, subjected to actinic irradiation to provide apolymeric (N-acyl-diezepine) surface exhibiting insolubility,hydrophobicity or water repellency.

The resistance of the irradiated polymeric materials to water and othersolvent materials, including solvent etching materials, allows for theuse of the pyridinium ylide polymers hereof in the production ofarticles wherein the irradiated polymer comprises an image pattern.Thus, a layer of pyridinium ylide polymer on a suitable substratematerial can be exposed to actinic irradiation in an imagewise manner toprovide a recordation or image of the subject in polymericN-acyl-diazepine. Exposure of the layer of pyridinium ylide polymer canbe accomplished through a negative, a photomask or the like. Unexposedareas can be removed by dissolution in water to provide the desiredimage in polymeric N-acyl-diazepine.

In FIG. 1 is shown in cross-section an edge view of an article 10 of theinvention including a suitable support material 12 carrying aphotosensitive layer 14 of a polymeric pyridinium ylide. Supportmaterial 12 can be glass, metal, plastic, cloth or any like substratematerial to which the polymeric pyridinium ylide can be suitablyapplied, as by coating, dipping or the like, and which can be subjectedto irradiation for conversion of the pyridinium ylide polymer to thecorresponding N-acyl-diazepine. The nature of the support will normallybe determined by the particular application for the product. Thus, ametallic support material may be preferred for the production oflithographic or like printing plates while glass or plastic supportmaterials such as polyethylene terephthalate may be preferred for theproduction of electro-optic display or like articles. The polymericpyridinium ylide layer 14 can comprise any of the photosensitivepolymers as described herein.

Article 10 carrying photosensitive polymer layer 14 can be subjected toany source of radiation sufficient to convert the ylide polymer to anN-acyl-diazepine as described hereinbefore, to provide any of a varietyof products. If desired, the irradiation can be applied to the surfaceof photosensitive polymeric layer 14 in a non-selective manner so as toprovide article 10 with a hydrophobic or waterproof layer 14. This willbe appropriate where, for example, a garment or other protective fabricmaterial 12 is desirably rendered hydrophobic or waterproof.

According to certain preferred applications for the pyridinium ylidepolymers hereof, the polymer will be irradiated selectively so as toprovide a pattern or image in polymeric N-acyl-diazepine. In FIG. 5 isshown a plan view of an article 40 comprising a support material 42carrying an image 44 in polymeric N-acyl-diazepine. such an article canbe conveniently provided, for example, by coating a substrate or supportmaterial 42 with a layer of polymeric pyridinium ylide. A stencil ormask corresponding to image 44 can be superposed upon the polymericpyridinium ylide layer. Exposure of the polymer layer, through thestencil or mask, effects the desired N-acyl-diazepine conversion and,provides a water-insoluble or hydrophobic area 44. Rinsing or washing ofthe article in water or other solvent results in removal of thewater-soluble pyridinium ylide polymer from unexposed (shielded) areas42 so as to define the desired image.

If desired, hydrophobic image material 44 can be dyed or otherwisecolored with material having an affinity for hydrophobic materials. Inthis case, support material can be composed of hydrophilic material soas to permit selective dyeing of image area 44 to the exclusion of thedyeing of support material 42. The resulting article can be used as aplate in duplication or like printing methods.

In FIG. 2 is shown a preferred article 20 suited to application in theproduction of a photoresist, electrode pattern or printed circuit. Shownon support 22 (comprised of glass, insulator board or the like) is alayer 26 of metal or other material that can be suitably etched byphysical or chemical means. Examples of such materials include copper,silver, indium tin oxide and iron/nickel alloy. The thickness of metallayer 24 can vary with the nature of the metal and the intendedapplication. On metallic layer 26 is a layer 28 of photosensitivepolymeric pyridinium ylide.

In FIG. 3 is shown an article 20A having a metallic electrode pattern 24formed on a support material 22. The pattern, comprised of metal and aprotective overlayer of polymeric N-acyl-diazepine, is formed by themethod of the present invention from article 20 shown in FIG. 2. Article20 is selectively irradiated through a stencil or photomask according tothe pattern defined by area 24 in FIG. 3. Radiation sufficient toconvert the polymeric pyridinium ylide to the correspondingN-acyl-diazepine polymer is employed. Removal of the mask and immersionof the photo-exposed article into a metal etching bath effects removal(in unexposed areas) of water-soluble pyridinium ylide polymer 28 andunderlying metal 26, leaving on support 22, the desired electrodepattern 24.

In FIG. 4a, there is shown in cross-section, along the lines 4a--4a ofFIG. 3, the article 20a. Metallic electrode material 26 is protected byhydrophobic N-acyl-diazepine polymer material 28a. If desired, polymericmaterial 28a can be removed from the metallic electrode material 26 bydissolving the polymer in an organic solvent such as dimethylformamide.The resulting article 20b is shown in FIG. 4b.

EXAMPLE 1

To a mixture of three grams of 1-amino-pyridinium chloride in 45 mls. ofethanol and seven grams of powdered anhydrous potassium carbonate, wasadded (with stirring and over a period of one-half hour) a solution of3.6 grams of 2-isocyanato-ethyl methacrylate in ten mls. oftetrahydrofuran, absolute. The resulting solution was filtered andevaporated to dryness. The residue was dissolved in a 100/15 mixture (byvolume) of trichloromethane and methanol and the resulting solution wasfiltered through a short column containing 15 grams of silica gel. Theproduction fractions were collected, evaporated to dryness andrecrystallized from methyl acetate. The product, a white crystallinesolid, was a monomer having the formula ##STR32## Molecular structurewas confirmed by thin layer chromatographic and nuclear magneticresonance techniques.

EXAMPLE 2

To a solution of 2.06 grams of 1-amino-pyridinium chloride in 35 mls. ofethanol, were added seven grams of powdered anhydrous potassiumcarbonate. To the resulting mixture, was added a solution of 1.8 gramsof methacryloyl chloride in five mls. of tetrahydrofuran, absolute. Theaddition was accomplished with vigorous stirring, and in a manner tomaintain the observed purple coloration. Upon completion of theaddition, the resulting solution was filtered and evaporated. Theresulting solid product was recystallized twice, using acetone, to yield1.75 grams of white needle-like crystals (70%). The product was amonomer having the formula ##STR33## The monomer showed good solubilityin water, methanol, trichloromethane; slight solubility in acetone andtetrahydrofuran; and insolubility in hydrocarbons. Molecular structurewas confirmed using thin layer chromatograhic and nuclear magneticresonance techniques.

EXAMPLE 3

A homopolymer of the monomer of Example 1 was prepared in the followingmanner. The monomer (0.7 gram) was dissolved in 8 to 10 mls. ofdistilled water in a polymerization tube and 30 mgs. ofazo-bis-4-cyano-pentanoic acid were added. Oxygen was removed inconventional manner by a repeated sequence of freezing and vacuum steps.The tube was sealed under vacuum and polymerization was effected byheating the tube to a temperature of from 64° to 70° C. overnight in abath. The resulting polymer was precipitated by introducing the productinto a 20- to 50-fold (vol./vol.) volume of acetone and the polymer wasrecovered.

The polymer was also prepared in a polymerization tube in the samemanner, except that, the polymer was precipitated into tetrahydrofuranand recovered. In each case, the resulting polymer showed solubility inwater, methanol, ethanol and trichloromethane.

EXAMPLE 4

A homopolymer containing repeating units of formula (XI) was preparedusing the procedure as set forth in Example 3. The monomer used for thepolymerization was prepared by the reaction ofN-(2-hydroxypropyl)-methacrylamide and N,N'-carbonyl-diimidazole; andthe reaction of the resulting amido with 1-amino-pyridinium chloride inthe presence of potassium carbonate, to convert the amido to thepyridinium aminimide monomer. The homopolymer prepared by polymerizationof the monomer showed solubility in water, methanol, ethanol andtrichloromethane.

EXAMPLE 5

In a polymerization tube, 336 mgs. of the monomer of Example 1, 267 mgs.of the monomer of formula (XXV), and 9.3 mgs. ofazo-bis-4-cyano-pentanoic acid were dissolved in seven mls. of a 1:1 (byvol.) mixture of water and methanol. Oxygen was removed using a repeatedsequence of freezing and vacuum steps, and the reaction tube was sealedunder vacuum. The tube was heated to 64° C. in a water bath overnight.The solvent was removed from the resulting polymerization product byevaporation and the residue was taken up into ten mls. oftrichloromethane. The copolymer was precipitated into about 400 mls. oftetrahydrofuran. The slightly yellow polymer was collected and dried ina vacuum oven at 45° C. for three hours. The product (450 mgs.; 75%yield) was a copolymer having the formula: ##STR34## The copolymershowed solubility in water, methanol, ethanol, and trichloromethane; andinsolubility in acetone, tetrahydrofuran, ether and ethyl acetate.

EXAMPLE 6

This Example illustrates the production of a pattern of iron-and-nickelalloy on a glass substrate.

Samples of glass plate material (2.54×2.54 cm.) having, on each, a layerof sputtered iron-and-nickel magnetic alloy (thickness about one micron)were cleaned with methanol. A four-percent (by weight) solution of thecopolymer of Example 5 was used to spin coat a layer of polymer onto themetal surface of each of the glass samples. Samples were coated usingwater as the solvent. Other samples were coated using trichloromethaneor methanol. Spin coating was performed at about 2000 rpm for twominutes.

Each sample was then selectively exposed and processed in the followingmanner. A resolution target (a photomask) was positioned over thepolymer-coated sample so as to permit exposure of areas not covered, andto prevent exposure of masked areas, according to the pattern of themask. The masked sample was then exposed for 20 minutes to theirradiation of a 12-watt long-wave (366 nm.) ultraviolet lamp. The maskwas removed and the sample was placed into an etching bath ofcommercially available etchant (Nickel Etchant, Type I, TranseneCompany, Inc. Rowley, Mass.) diluted 1:3 with water. Polymer (pyridiniumaminimide) and underlying metal, in the unexposed areas of the sample,were removed from the sample by the action of the etching composition.Conversion of polymeric pyridinium aminimide to the correspondingN-acyl-diazepine, in areas of exposure, provided protection of theunderlying metal against removal by the etching bath. The result was aproduct having, in exposed areas, a metallic pattern corresponding tothe pattern of the mask.

EXAMPLE 7

This Example illustrates the production of a copper pattern on printedcircuit board material.

An insulator board material having a layer of copper thereon (acommercially available material used for the production of printedcircuit boards) was treated in the following manner. Samples of theboard material (2.54×2.54 cm.) were spin coated (over the copper-cladsurface of the board) with a solution of the copolymer of Example 5,using the procedure described in Example 6. The samples were then maskedand photoexposed as described therein. Upon removal of the mask, thesamples were placed into a bath of aqueous ferric chloride etchingmaterial. Areas of polymeric pyridinium aminimide and underlying copperwere removed (in unexposed areas) by the effect of the ferric chlorideetching bath. Conversion of the polymeric pyridinium aminimide to thecorresponding N-acyl-diazepine (in exposed areas) provided protectionfor the underlying copper against removal by the etching bath. Theresult was a printed circuit board having a copper pattern thereoncorresponding to the pattern of the mask.

EXAMPLE 8

This Example illustrates the production of an image in N-acyl-diazepinepolymer on a silicon wafer material.

Samples of commercially available silicon wafers were spin coated with a3% solution of the copolymer of Example 5. Samples were coated usingwater as the solvent; other samples were coated using trichloromethane.Spin coating was performed at 2000 rpm for two minutes. The coatedsilicon wafers were exposed through a resolution target, using a 12-wattultraviolet (366 nm.) lamp. Exposure times ranged from 21 to 25 minutesdepending upon intensity. The photoexposed wafers were immersed into awater bath for about five to ten seconds to remove pyridinium aminimidepolymer in unexposed regions. The result was an image inN-acyl-diazepine polymer of about 0.05 micron thickness corresponding tothe pattern of the resolution target. The image showed good resolutionof lines of 2.5 micron spacing.

Adhesion of the polymeric image to the wafers was evaluated by stickinga strip of cellophane tape onto the polymer image; removing the tapetherefrom; and inspecting for evidence of removal of polymer image.Inspection showed no evidence of such removal.

EXAMPLE 9

Using the method described in Example 8, images were prepared on quartzand cellophane substrate materials from the polymers of Examples 3, 4and 5. Similar results were obtained in each case in that images of theresolution target in N-acyl-diazepine polymer were recorded on thesubstrate materials. Each of the samples, using the adhesion testdescribed in Example 8, showed no evidence of removal of image uponremoval of the cellophane tape.

EXAMPLE 10

This Example illustrates the use of a pyridinium aminimide polymer forthe hydrophobization of a substrate surface.

Samples of quartz and cellophane sheet material were coated withpolymers of Examples 3, 4 and 5, using the method described in Example8. The samples were irradiated non-selectively, i.e., without aresolution target or mask. The polymeric pyridinium aminimide coatingwas in each case converted by the photoexposure to a correspondingN-acyl-diazepine polymer exhibiting hydrophobicity and water repellency.Application of water to the exposed polymer surface and tilting thereof,showed the beading and roll-off without a remaining trace of the appliedwater. In contrast, similarly coated samples which were notphotoexposed, showed spreading (wetting) of added water and evidence ofdissolution of the pyridinium aminimide polymer.

What is claimed is:
 1. A method for preparing an article carrying alayer of water-insoluble or hydrophobic protective polymer whichcomprises subjecting to actinic radiation, an article comprising asupport carrying a layer of photosensitive polymeric pyridinium ylide,said article having between said support and said photosensitivepolymeric pyridinium ylide, a layer of material etchable by physical orchemical means, said actinic radiation being sufficient to convert saidpolymeric ylide to a water-insoluble or hydrophobic N-acyl-diazepineprotective polymer.
 2. A method for preparing an article carrying animage pattern of water-insoluble or hydrophobic protective polymer whichcomprises subjecting to an imagewise exposure to actinic radiation, anarticle comprising a support carrying a layer of photosensitivepolymeric pyridinium ylide, said imagewise exposure being effective toexpose predetermined areas of said layer of photosensitive polymericpyridinium ylide to said actinic radiation, while other predeterminedareas of said layer of photosensitive polymeric pyridinium ylide areshielded from exposure to said actinic radiation, thereby to imagewiseselectively expose said layer of photosensitive polymeric pyridiniumylide and to form water-insoluble or hydrophobic N-acyl-diazepineprotective polymer in said selectively exposed areas.
 3. The method ofclaim 2 wherein the areas of said layer of photosensitive polymericylide shielded from exposure to said actinic radiation are removed fromsaid support, thereby to provide on said support a predetermined patternof said water-insoluble or hydrophobic N-acyl-diazepine protectivepolymer.
 4. A method for forming a photoresist which comprises the stepsof: selectively exposing to actinic radiation, a photosensitive articlecomprising a support carrying a layer of metal, and having over saidmetallic layer, a layer of photosensitive polymeric ylide, saidselective exposure being effected by exposing predetermined areas ofsaid photosensitive layer to said actinic radiation while shieldingother predetermined areas of said photosensitive layer from exposure tosaid actinic radiation, said actinic radiation being sufficient toconvert said photosensitive polymeric ylide in said areas of exposure toa water-insoluble or hydrophobic N-acyl-diazepine protective polymer;and removing said photosensitive polymeric ylide from said areas ofnon-exposure.
 5. The method of claim 4 wherein said metal is removed bychemical or physical means from said areas of non-exposure, thereby toprovide on said support, a predetermined pattern comprisingpredetermined areas of metal having thereover, said water-insoluble orhydrophobic N-acyl-diazepine protective polymer.
 6. The method of claim5 wherein said metal removal is effected by a chemical etching solutionto which said water-insoluble or hydrophobic N-acyl-diazepine protectivepolymer is resistant.
 7. The method of claim 4 wherein said supportcarrying a layer of metal comprises a metal-clad insulator board.
 8. Themethod of claim 1 wherein said article is subjected to said actinicradiation in an imagewise manner.
 9. The method of claim 2 wherein saidphotosensitive polymeric pyridinium ylide comprises a polymeric backbonehaving pendant therefrom or as part of said backbone, a pyridinium ylidemoiety of the formula ##STR35## wherein X is ##STR36## or SO₂ --, whereR¹ is alkyl, aryl, alkaryl or aralkyl.
 10. The method of claim 9wherein, in said pyridinium ylide moiety, X is ##STR37##
 11. The methodof claim 2 wherein said photosensitive polymeric pyridinium ylidecomprises a plurality of repeating units having the formula ##STR38##wherein L is an organic linking group and m is the integer one or two.12. The method of claim 11 wherein said photosensitive polymericpyridinium ylide comprises a plurality of repeating units having theformula ##STR39## wherein L is an organic linking group, m is theinteger one or two, and R is hydrogen, halo or lower alkyl.
 13. Themethod of claim 12 wherein in said repeating units, L is a divalentradical of the formula ##STR40## --Ar--; or --Ar--R³ --, wherein, ineach radical, R is hydrogen, alkyl, aryl, alkaryl or aralkyl, and R³ isa divalent alkylene radical.
 14. The method of claim 12 wherein in saidrepeating units, R is hydrogen, or methyl, X is ##STR41## m is two, andL is a divalent radical of the formula ##STR42## wherein R³ is1,2-ethylene.
 15. The method of claim 12 wherein said photosensitivepolymeric pyridinium ylide includes repeating units from ethylenicallyunsaturated copolymerizable monomer.